(from Alex McEachern) Power Quality Newsletter - December 2009
In this Power Quality Newsletter
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Smart Grid
The Smart Grid: Energy, and Power Quality too?

Nobody seems to be quite sure exactly what the "Smart Grid" is, but advocates seem to be certain it will both save energy and improve power quality.

My own favorite definition, with credit for the thought to Math Bollen, is that the Smart Grid uses communication and intelligence, instead of brute force, to maintain the necessary balance between generators and loads on a grid. At times, "balancing" might mean adding more generators, such as distributed generation. At other times, balancing might mean turning off loads, or giving customers incentives to turn off loads. And at still other times, balancing might mean automatically reconfiguring distribution lines.

But given all the switching of generators and loads and lines that the Smart Grid implies, it's not at all clear to me that power quality will get better. Switching loads and generators and distribution on and off almost always causes disturbances. So it seems to me that power quality might get worse.

An interesting new Working Group has been formed in the International Union for Electricity Applications under the leadership of Professor Bollen that is looking into this question, especially with respect to voltage sags. Francisc Zavoda of Hydro Quebec is starting work in this area. And Claudia Imposimato leads the IEC Working Group on power quality compatibility -- emissions and immunity -- for distributed generation. Please let me know if you're interested in these subjects, and would like contact information. I'm sure the UIE Working Group would be especially interested in technical contributions from anywhere in the world.

PQube kit
Of course, like most discussions in my life these days, talking about the Smart Grid leads me back to PSL's PQube. My old friend Larry Finch, a wise and experienced venture capitalist, points out that PSL's low-cost lab-grade PQube energy-and-power-quality monitor is, in fact, the ideal end-point for verifying the effectiveness of the SmartGrid.

Erich Gunther's SmartGrid review of the PQube
One of the most admired experts in the Smart Grid world, Erich Gunther of Enernex, has written an excellent review, covering the strengths (and weaknesses) of the PQube for Smart Grid applications.

Have some year-end budget? If you have just a couple of thousand dollars of year-end money, think about ordering a PQube to play with - it's a mind-opening new tool for power engineers. To get started quickly, I'd suggest the PQube Power Quality Kit. Please let me know if you have any questions - Alex@PowerStandards.com.

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Cruise ship microgrid     Submarine microgrid     Navy ship microgrid
Shipboard energy and power quality - experts on microgrids, too

I've been seeing more PQube applications aboard ships (and on remote-operated undersea vehicles, too, but that's a different topic), so I've been spending some time recently getting my sea legs and looking into shipboard power.

The engineers who work in this area are the real experts on microgrids - after all, from an electric power perspective, that's what a ship is, and these engineers don't have a big power grid to fall back on when something goes wrong. And they know a lot about corrosion protection, too. Good people to learn from.

There are the usual power quality issues for sensitive shipboard equipment -- sags, impulses, harmonics -- plus some interesting earth/ground issues. When we're on land, we don't worry much about earth currents, except from a safety perspective. But on board a ship, earth currents can cause plating and corrosion of the ship's hull - a very bad thing.

One of the big surprises, to me, was that many older ships don't monitor energy consumption, even when they're hooked up to shore power. They're charged a flat rate no matter how much or how little energy they use, just like airplanes hooked up to GPU's at airport gates. We'll get that corrected - energy is too valuable these days. And some of these ships use a LOT of energy...

New! ABS certifies PQube for shipboard applications
I'm proud to announce that ABS, which is the certification body for ocean-going vessels, has just awarded PSL's PQube energy/power quality monitor a Certificate for shipboard use, so now you can include the PQube in any of the 150 million gross tons of ships that are in the ABS-certified fleet (did you realize there were that many ships in the world?). The PQube and its accessory modules are type-approved by ABS as Power Monitoring Units under ESWBS Code 50400 "Instruments and Instrument Boards".

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US and British frequency graphs  
World-wide frequency instability

I have the impression -- and it's just a personal impression -- that grid frequencies around the world are becoming less stable.

Click on the picture above, for example, to see graphs, straight from PQubes, of November's second-by-second grid frequency in the western United States (top graph) and in England (bottom graph). I'm surprised by the instability - for the entire month, of course, the frequency averages exactly 60.000 Hz or 49.999Hz, but from minute to minute there are significant changes. And these are big, stable grids.

Or take a look at the frequency in Tokyo, recorded on a PQube in my hotel room last week:
Tokyo frequency graph

It's possible, of course, that frequencies has always looked like this, and I'm just becoming more aware of it because we have so many PQube instruments installed all over the world, making me more sensitive to frequency variations in Dubai, and Malaysia, and China, etc.

But it's also possible that grid frequency is becoming less stable. Perhaps that's because grids are being operated closer to their limits, or perhaps because the load variations are more extreme and abrupt, or perhaps -- I hope not -- it's a result of increased penetration of distributed generation.

Has anyone published a paper on the history of grid frequency stability? If you know, please let me know. We're starting work at PSL on new ways of measuring grid stability, especially where there's lots of distributed generation, and I'm looking forward to learning more.


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LBNL substation
Upcoming visits

Last month, I enjoyed teaching (and learning) in Korea, and was given the opportunity to present one of the keynote speeches at China's National Power Standards conference.

This past week, I met with customers in Tokyo and joining discussions with NTT-F, EPRI, Intel, Fujitsu, Hitachi, and others regarding 380-volt DC power for buildings and data centers. And on 14 January, I'm looking forward to teaching a brief seminar at Lawrence Berkeley National Laboratory on energy measurements there, using their network of PQubes as a case study.

Do let me know if you would like to get together at any of these locations - my detailed calendar is at Alex.McEachern.com.

I hope you have a happy, peaceful holiday season, and a productive 2010!
Cats at home

With best wishes -

Alex McEachern
Alex@PowerStandards.com
Power Standards Lab
1201 Marina Village Drive #101      
Alameda, California 94501 USA
TEL ++1-510-522-4400
FAX ++1-510-522-4455

Alex McEachern

 

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